Lampholder



Feb. 4, 1964 D. G. KIMBALL 3,120,416

LAMPHOLDER Filed June 15, 1961 2 Sheets-Sheet 1 g V A't'orwey.

D. G. KIMBALL 'Feb. 4, 1964 LAMPHOLDER 2 Sheets-Sheet 2 Filed June 15, 1961 3d, Z m 6% @a m w e W 1w v 2 1.. w My m a w United States Patent 3,120,416 LAMPHOLDER Donald Glfirmball, Stratford, Conn., assignor to General Electric Company, a corporation of New York Filed June 15, 1961, Ser. No. 117,330 6 Claims. (U. 339-45) This invention relates to an improved socket, and in particular to an improved lampholder for use in projectron apparatus or analogous devices.

In most, if not all, of the conventional picture projec tron devices, an exciter lamp is mounted in a lampholder, with both lamp and lampholder in close quarters relative to their surrounding structure. Such an arrangement of the lampholder and lamp affords very little finger space to enable grasping of the lamp by the fingers for its removal from the lampholder. It is, therefore, advantageous to provide a means for facilitating the removal of the exc1ter lamp from the lampholder. To achieve this result, prior art projector lampholders incorporating such a means have necessitated relatively complicated structure and as a consequence thereof, they are relatively expensive to manufacture. it has, therefore, been deemed desirable to provide a lampholder for a projection device, with a new and improved means for facilitating the removal of the exciter lamp from the lampholder. It has also been found to be advantageous to decrease the number of parts required for a lampholder incorporating the removal facilitating means. This, of course, helps to reduce the cost of such a lampholder to the customer.

An important object of this invention is to provide an improved socket with a novel and low cost means for efliciently removing a tubular member therefrom.

It is another object of the present invention to provide an improved lampholder with a simplified and readily manufacturable means for forcing a lamp outwardly from its seated position.

his a further object of the present invention to provide an improved projector lampholder having an integral means for pivotally supporting a lever which facilitates the removal of an exciter lamp from the lampholder.

. In carrying out my invention, in one form thereof, there is provided a lampholder for receiving a lamp with a central positioning projection formed on its bottom. This lampholder comprises a one-piece base with a central aperture formed therein for receiving the lamp projectron, and a bearing surface formed therein for pivotally supporting a lever. The lever has an integral curved surface formed on it which is disposed in complementary bearing relationship with the bearing surface of the base. With the lever pivot-ally supported on the base it may be manually operated by an appropriate tool and a portion of the lever engages the projection of the seated lamp to force the lamp from the lampholder. By means of this improved structural arrangement, the removal of a seated lamp from the lampholder is expeditiously implemented.

Further aspects of my invention will become apparent hereinafter, and the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which I regard as my invention. The invention itself, however, both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description when read in conjunction with the accompanying drawings:

FIG. 1 is a perspective view of the improved lampholder embodying the present invention, with the lampholder being shown in supporting engagement with an appropriate projector lamp;

FIG. 2 is a perspective view of the improved lampholder, illustrating the positioning ears thereof;

' FIG. 3 is a plan view of the improved lampholder;

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FIG. 4 is a bottom view of the improved lampholder;

FIG. 5 is an enlarged fragmentary View of the central aperture of the lampholder shown in FIG. 3;

'FIG. 6 is a sectional view taken along the line 66 of FIG. 5, to illustrate the tapered configuration of the ribs of the central aperture;

FIG. 7 is a plan view of one form of a slide projector wherein my improved lampholder may be expeditiously utilized, with the cover of the projector housing broken away to illustrate the interior thereof inclusive of the lampholder and the lamp;

FIG. 8 is a View taken generally along the line 88 of FIG. 7, partially broken away and partially in section, with the bottom portion of a projector lamp overlying the lampholder and spaced therefrom;

FIG. 9 is a sectional View of the lampholder, taken generally along the line 99 of EEG. 7, with the bottom portion of a mating projector lamp shown in the position wherein it is disposed after it has been forced outwardly from its seated position by the ejector lever;

FIG. 10 is a fragmentary view of the lampholder to show the configuration of the slots formed in the base for support and movement of the ejector lever; and

FIG. 11 is a perspective view of the ejector lever of the lampholder.

Referring first to FIG. 1 of the drawings, there is shown a projector exciter lamp 1 which includes a supporting portion or base 3. Base 3 of exciter lamp 1 is cylindrically configured and is adapted to be securely engaged by and positioned within projector lampholder 5. The illustrated exciter lamp 1 is of a type generally employed in large numbers in the picture projection industry. This lamp 1 is of tubular construction and comprises an elongated and evacuated cylindrical envelope '7 having a hemispherically configured outer end 9 It will be understood that one or more suitable filament elements (not shown) are arranged within envelope 7. As shown in FIGS. 8 and 9, the cylindrical bottom portion 11 of lamp 1 is encased by and afiixed to the lamp supporting base 3. To guide lamp 1 into lampholder S and also to help support the lamp therein, a generally cylindrical projection 13 is formed on the bottom 15 of supporting base 3. Projection 13 is centrally disposed and protrudes axially outwardly in perpendicular fashion from bottom 15. For electrically connecting the internal filament elements of the lamp to appropriate mating contacts of the lampholder 5, male type pin contacts 17 have been provided. Pin contacts 17 project outwardly from bottom 15 of lamp base 3 to a lesser degree than projection 13 (as shown in FIGS. 8 and 9), being radially disposed from and in parallel relationship to the longitudinal axis of the tubular lamp 1.

Attention is now directed to the structure of lampholder 5, wherein my invention has been advantageously employed. Certain features of this lampholder, other than those claimed herein, are the invention of Wallace R. Francis, and are described in detail and claimed in the copending application Serial No. 117,222 of said Francis, filed concurrently herewith and assigned to the same assignee as the present invention. To enable lampholder 5 to expeditiously seat exciter lamp 1 and also furnish a simplified means for readily fastening the lampholder to appropriate supporting structure, as shown in FIGS. 14, the unitary one-piece base member 19 has been provided. Base member 19 is of a molded insulating material such as one of the heat resistant plienolics, and it essentially includes a generally cylindrical body 21 (FIG. 2) with substantially parallel top and bottom walls 23 and 25, an gularly spaced L-shaped positioning portions 27 and 29 (FIGS. 2 and 3), and supporting Wings 31 which extend radially outwardly from outer surfaces 32 of positioning portions 29 (FIG. 9).

To provide the base member 19 with an integral seat for securely receiving and positioning the projector lamp 1, the L-shaped positioning portions 27 and 29 (FIG. 3) are arranged about the upper periphery of body 21 (FIG. 8), in oppositely disposed and angularly spaced pairs. F or example, as shown in FIGS. 2 and 3, the positioning portions 27 are disposed on opposite sides of the longitudinal axis 34 of the lampholder and the positioning portions 29 are also disposed on opposite sides of the axis of the lampholder and spaced angularly approximately 90 from the positioning portions 27. Each of the positioning portions 27 and 29 includes a bottom section 33 (FIG. 3) which extends transversely to the axis of the lampholder and has a top surface coplanar to top wall 23. The top surface of section 33 (as illustrated in FIG. 8) helps to support bottom 15 of lamp base 3 adjacent the outer rim of bottom 15. Each of the L shaped portions 27 and 29 also includes a curved upright car 35. Ears 35 project perpendicularly outwardly from the top surfaces of bottom sections 33 and have inner cylindrical surfaces 37 formed thereon. The cylindrical surfaces 37. as shown in FIG. 3, are molded as an integral part of base member 19 so that they are disposed in juxtaposed relationship to adjacent outer surfaces of the supporting portion 3 of the projector lamp 1 when the lamp is seated in the lampholder. (See FIG. 8.) Thus, when the lamp is seated, the cylindrical surfaces 37 of the ears 35 serve to grip or hug the adjacent cylindrical periphery of the lamp and laterally position it within the lampholder. By molding the upright ears 35 as an integral part of the lampholder base member 19, a rigid and inexpensive means is thereby achieved for laterally positioning and supporting the lamp within the lampholder.

To enable base member 19 of the lampholder to be readily fastened to an appropriate supporting means, the aforementioned fastening wings 31, as shown in FIG. 8, are projected radially outwardly from the positioning portions 29. Wings 31 include apertures 39 for receiving screws 41. The screws 41 extend through apertures 39 of the wings and are threaded into engagement with tapped openings in supporting struts 43 of a projection ap paratus 45 (FIG. 7). Projection apparatus 45 is a typical device wherein lampholder 5 may be expeditiously utilized, and it includes a relatively small box-shaped housing 46 wherein the lampholder 5 is supported, magnifying lenses 43a, 48b, and 480, and telescopically supported focusing lens 5%). When the projector lamp 1 is seated in lampholder 5 and switch toggle arm 52 is moved to the appropriate position, switch contacts (not shown) close an electrical circuit which includes the contacts of the lampholder. The filament elements of the lamp are then energized and a slide (not shown) with an image thereupon may be magnified by the lenses 48a, 48b, 48c, and 50, and projected upon a screen.

To guide the cylindrical projection 13 of base portion 3 of the exciter lamp 1 into lampholder 5, and at the same time provide a rigid integral supporting means for the cylindrical projection 13 of the lamp, as shown in FIGS. 3 and 4, base 19 has a generally cylindrical aperture or recess 47 formed therein. In the illustrated lampholder, aperture 47 is centrally disposed relative to lampholder axis 34 and opens into top wall 23 and bottom Wall 25 of the lampholder 5. The axis 34 of lampholder 5 is, of course, collinear with the longitudinal axis of lamp 1 when the lamp is seated. On the inner cylindrical Wall of aperture 47, a plurality of angularly spaced parallel ribs 49 are formed. These ribs 49 are elongated and disposed radially from the axis 34 of the lampholder, being also V-shaped in cross section (FIG. 5) and tapered radially inwardly in depth between the top and bottom walls 23 and '25 (FIG. 6). Thus, the general periphery of aperture 47 at top wall 23 of base 19 (except for slot 53) is in the configuration of an uninterrupted circle (FIGS. 3 and 5), and the general periphery of aperture 47 at bottom wall 25 of the lampholder base (except for 4 slot 53) is in the configuration of an interrupted circle having angularly spaced and inwardly pointed V-shaped projections (FIG. 4). The purpose and function of the tapered ribs '49 shall become apparent hereinafter.

When cylindrical projection 13 of the exciter lamp 1 15 inserted into the central aperture 47 of lampholder 5, an enlarged longitudinally extending rib 51 (FIG. 9) which is formed on the outer surface of projection 13 must first enter elongated keyway slot 53 of aperture 47 (FIG. 5). Slot 53 extends longitudinally between the top and bottom walls of lampholder body 21 and assures the proper angular relationship between lamp 1 and lampholder 5 for mechanical and electrical engagement of the contacts.

When lamp guiding projection 13 is properly aligned with and then inserted into lampholder aperture 47, the projection 13 encounters an increasing frictionalres1stance as bottom 56 moves between top wall 23 and bottom wall 25 of the aperture. For example, when the bottom 56 of projection 13 first enters aperture 47 at top wall 23 of the lampholder, the cylindrical surface of projection 13 encounters a relatively smooth upper rim which has a slightly larger diameter than the principal diameter of projection 13. The lamp projection 13 thus readily entcrs aperture 47 upon the proper angular alignment of guiding rib 51. The lamp 1 is then, of course, pushed into the lampholder 5 and guided by movement of pro jection 13 within the aperture 47. As the lamp projection 13 rides downwardly through the aperture 47, as shown in FIG. 9, toward its seated position, it eventually becnnes frictionally engaged by the innermost inclined edges 55 of tapered ribs 49. When central projection 13 of exciter lamp 1 has reached its seated position 13a (as shown in FIG. 9), the complementary relationship between the tapered ribs '49 of aperture 47 and the outer cylindrical wall of projection 13 is such that a press fit is achieved. Bottom 56 of lamp projection 13 is then disposed underneath the bottom wall 25 of the aperture (as shown in FIG. 9), and appropriate portions of rib edges 55 are in secure gripping engagement with adjacent cylindrical surfaces of lamp projection 13. The particular construction of base member 19 for mounting lamp 1 thereon (including ears 35 and ribs 49) comprises the invention of Wallace R. Francis, and this construction and arrangement are described and claimed in his aforesaid copending application Serial Number 117,222.

To furnish an appropriate means for electrically and mechanically engaging the pin contacts '17 of exciter lamp 1, as shown in FIGS. 3, 4, and 8, female contacts 57 have been provided. Contacts 57 are of a type well known '11 the art, and they each include a pair of L-sh'aped fingers 59. The fingers 59 include upright portions 61 and outer or transverse ends 65. Portions 61 are in= clined slightly toward each other so that they produce a tapered contact slot 53 having its maximum width at the bottom thereof (FIG. 8). The outer or transverse ends 65 of the fingers 59 extend in opposite directions from slot 63 and provide a pair of shoulders 67 which engage internal steps 69 of contact receiving recesses 71. On the bottom end 73 of each of the female contacts 57 (as shown in FIG. 8) there is provided a terminal blade portion with a detent hole therein for engagement with an associated quick connecting terminal. Between the bottom end 73 of each of the contacts 57 and the L-shaped fingers 59 thereof, a pair of laterally extending tabs 75 are formed. The tabs 75 are bent over, as shown in FIG. 4, to perpendicularly engage recessed bottom wall surfaces 79 and thereby secure the contacts to the base member 19. An entrance for each of the female con tacts 57 is provided by tapered surfaces 81 thereof. These tapered surfaces 81 are formed in the top of transverse. ends 65 (viewing FIG. 8) and converge inwardly in a driection toward terminal blades 73 to facilitate the introduction of the pin contacts 17 of the exciter lamp 1.. Frusto-conical seats 32 (FIG. 3) are also molded on each.

w lls side of recesses 71 at top wall 23 to help guide the pin contacts 17 into engagement with female contacts 57.

Turning now, to a very important aspect of my invention, to enable one to readily remove the exciter lamp 1 from my improved lampholder 5, as shown in FIGS 9-11, a pivoted ejector lever 83 has been provided. Lever 83 has a generally hook-shaped configuration and includes an integral arcuate bearing surface 85, connecting section 87, and arcuate force transmission section 89.

To describe the structure of my lever 83 in greater detail, it is a fiat element and may be stamped from a thin sheet of suitable metal. The bearing surface 85 of lever 83 has a partially disc-shaped configuration. Between bearing surface 85 and the arcuate section 89, there is a generally L-shaped slot 91 (FIG. 11). Upper surface 93 (viewing FIG. 9) of the connecting section 87 (FIG. 11) presents a flat outer edge which is parallel to the top wall 23 of insulating base member 19 when the exciter lamp 1 is seated in the lampholder 5. Actuating notch 95 is formed in upper surface 93 close to the juncture of sections 87 and 89 (PEG. 9). Notch 95 includes a diagonal working surface 97 that serves as a camming edge to allow clearance for an appropriate tool 99 into the bottom of notch 95. The angle of working surface 97 and configuration of notch 95 prevent tool 99 from slipping out of or jamming in notch 95 when upper surface 93 of the lever is depressed downwardly (FIG. 9).

The pivoted ejector lever 83 is mounted for rotation in the lampholder 5, as shown in FIG. 10, in radial slots 191, 1%, and 165. Slots 101, 153, and 195 are formed in the top, side, and bottom walls, of base member 19. These slots are narrow in configuration and are disposed in a plane which includes the lampholder axis. As shown in FZGS. 9 and 10, the combination of the slots fill, 103, and 135 also presents a substantially J-shaped profile. Slot lid 1 is formed in the top and side walls of member 19 to provide an arcuate bearing surface 197 for pivotally supporting arcuate surface 35 of lever 83, and lip M9 for limiting downward movement of the lever. Slot 193 is formed in the side and bottom walls of member 19 (i.e., at the corner described by these walls), and provides clearance for rotational movement of the lever 83 to its downward or actuated position. Slot 165 is formed in the bottom of base member 19, and it provides clearance for the rotational movement of stepped projection 111 formed on the inner arcuate surface of the lever 83.

Turning now to a detailed explanation of the operation of ejector lever 83, attention is further directed to FIG. 9. When exciter lamp l is being seated in lampholder 5, cylindrical projection 13 moves downwardly into dotted position 13a, and the actuating tip 112 of lever element 83 is thereby moved into dotted position 112a. To explain this movement in more explicit fashion, as exciter lamp 1 moves into its seated position, the pivoted ejector element E53 is forced in a counterclockwise direction of rotation (viewing FIG. 9) to its dotted cocked position by engagement of bottom 56 of lamp projection 13 with lever tip 1. .2. Upper surface 93 of lever element 83 is then generally parallel to the top wall 23 of the lampholder, as it is shown in dotted position 93a of FIG. 9. A person who wishes to remove the exciter lamp from the larnpholder then may conveniently move the shoulder of a suitable tool 99 downwardly from above projector lamp housing as into depressive engagement with working surface 97 of actuating notch 95. Lever 33 thereupon pivots about its axis of rotation 113 in a clockwise direction of rotation to the position where it is shown in full in MG. 9. During this movement, actuating tip 112 of the lever 83 engages the bottom 56 of cylindrical projection 13 of the exciter lamp and propels it upwardly to the position where it is shown in full in FIG. 9. The lamp 1 may then be readily removed from the larnpholder 5 by a simple pulling motion, or inversion of the lampholder.

When lamp 1 is seated in my improved lampholder 5, the abrupt shoulder 111a of stepped projection 111 of lever 83 engages the radially outermost step 114 of slot (FIG. 9). This limits movement of lever 83 in a counterclockwise direction of rotation (viewing FIG. 9). Upon the depression of lever 83 to its actuating position (where it is shown in full in FIG. 9), lip 169 of base member 19 contacts upper end 115 of the L-shaped slot 91 (FIG. 11). This limits movement of lever 83 in a slockwise direction of rotation (viewing FIG. 9).

It will now, therefore, be seen that by means of the present invention, I have provided an improved socket such as herein illustrated in a projector lampholder, with a simple and eliicient means for implementing the removal of a tubular member such as a projector lamp. For example, to illustrate the simplicity of this lampholder, the ejection means thereof requires only two parts, the base and the ejector lever. It will also be understood that the socket of the present invention is compact, and readily manufaeturable.

While in accordance with the patent statutes, I have described what at present is considered to be the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and I, therefore, aim in the following claims to cover all such equivalent variations as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

ll. In a lampholder for receiving a lamp with a central positioning projection formed on the bottom thereof, an insulating base, an aperture disposed in said base for reeeiving the projection, bearing surface means formed integrally into said base, and a one-piece, generally planar and C-shaped member having an edge of one end pivotal'ly supported upon said surface means, the other end of said member being engageable with the projection of the lamp when the lamp is seated in said lampholder thereby to propel the lamp from said lampholder.

2. In a projector 'lampholder for receiving a lamp with a central positioning projection formed on the bottom thereof, an insulating base including top and bottom walls, an aperture disposed in said base for receiving and seating the projection, a bearing surface formed integrally to said base, and a one-piece, generally planar and C-shaped member having an edge of one end pivotally supported upon said surface and the other end of said member being engageable with the projection of the lamp when the lamp is seated in said lampholder, said edge of said member having an integral curved surface in complementary bearing relationship with the bearing surface of the base and a tool receiving indentation intermediate said ends facing in the same direction as the top wall of the insulating base, said member being actuated by engagement of an appropriate tool with said indentation thereby to pivot the member upon the bearing surface of the base and cause said member to propel the lamp from said lampholder.

3. In a projector lampholder for receiving a lamp with a central positioning projection formed on the bottom thereof; an insulating base including top and bottom walls; an aperture disposed in said base for receiving said projection; a bearing surface formed integrally to said base; and a flat coplanar element pivotally supported upon said surface and engageable with the projection of said lamp when the lamp is seated in said lampholder; said element being hook-shaped and comprising a partially disc-shaped end'with a curved surface thereon, said end being disposed in complementary bearing relationship With the bearing surface of the base, a lamp engaging end spaced radially and angularly from the center of said disc-shaped end and engageable with the projection of the lamp, and a tool receiving notch formed on an outer edge of said element, said notch facing in the same direc- 7 tion as the top wall of the insulating base; said element being actuated by engagement of an appropriate tool With said notch thereby to pivot the partially disc-shaped end of the element upon the bearing surface of the base and force the lamp engaging end of the element to propel the lamp from said lampholder.

4. For a projection apparatus wherein an exciter lamp is employed in a relatively diminutive housing to illuminate and project an image which is magnified by a plurality of lenses, an improved projector lampholder for receiving an exciter lamp with a central positioning projection formed on the bottom thereof, said lampholder comprising a molded insulating base including top and bottom walls; the longitudinal axis of said lampholder being centrally disposed through and perpendicularly re lated to said top and bottom walls; slotted means formed integrally to said base and radially disposed in a plane which includes said lampholder axis, said slotted means having a substantially J-shaped profile which includes an inner arcuate bearing surface; and a flat coplanar element pivotally supported upon said bearing surface and engageable with the projection of said lamp when the lamp is seated in said larnpholder; said element being hook-shaped and comprising a partially disc-shaped end with a curved surface thereon, said end being seated in complementary bearing relationship with the bearing surface of said slotted means, a lamp engaging end spaced radially and angularly from the center of said disc-shaped end and engageable with the bottom of the projection of the lamp, and a tool receiving notch formed on an outer edge of said element, said notch facing in the same direction as the top Wall of the insulating base; said element being actuated by engagement of an appropriate tool with said notch thereby to pivot the partially disc-shaped end of the element upon the bearing surface of the base and force the lamp engaging end of the element to propel the lamp from said lampholder.

5. In a projector lampholder for receiving a lamp with a central positioning projection formed on the bottom thereof; an insulating base including top and bottom walls; an aperture disposed in said base for receiving said projection; a bearing surface formed integrally to said base; and a flat coplanar element pivotally supported upon said surface and engageable with the projection of said lamp when the lamp is seated in said lampholder; said element being hook-shaped and comprising a partially disc-shaped end with a curved surface thereon, said disc-shaped end being disposed in complementary bearing relationship with the bearing surface of the base, a lamp engaging end spaced radially and angularly from the center of said disoshaped end and engageable with the projection on the lamp, a step formed upon said element, said stop being engageable with an associated second step formed upon said base to limit pivotal motion of said element in one direction of rotation, a shoulder formed upon said element adjacent said disc-shaped end, said shoulder being engageable with an associated lip formed in said base adjacent said bearing surface to limit pivotal motion of said element in the other direction of rotation, and a tool receiving notch formed on an outer edge of said element, said notch facing in the same direction as the top wall of the insulating base; said element being actuated by engagement of an appropriate tool with said notch thereby to pivot the partially disc-shaped end of the element upon the bearing surface of the base and force the lamp engaging end of the element to propel the lamp from said lampholder.

6. In a projector lampholder for receiving a lamp with a central positioning projection formed on the bottom thereof; an insulating base including top and bottom walls; an aperture disposed in said base for receiving said projection; a bearing surface formed integrally to said base; and a fiat coplanar element pivotally supported upon said surface and engageable with the projection of said lamp when the lamp is sea-ted in said lampholder; said element being hook-shaped and comprising a partially disc-shaped end with a curved surface thereon, said end being disposed in complementary bearing relationship with the bearing surface of the base, and a lamp engaging end spaced radially and angularly from the center of said disc-shaped end and engageable with the projection on the lamp; said element being actuated by engagement of an appropriate tool therewith thereby to pivot the partially disc-shaped end of the element upon the bearing surface of the base and force the lamp engaging end of the element to propel the lamp from said lampholder.

References Cited in the file of this patent UNITED STATES PATENTS 2,051,425 Schlums Aug. 18, 1936 2,476,735 Johnson July 19, 1949 2,570,104 De Reamer et al Oct. 2, 1951 2,703,869 Haradcn Mar. 8, I955 FOREIGN PATENTS 445,486 Great Britain Apr. 14, 1936 

1. IN A LAMPHOLDER FOR RECEIVING A LAMP WITH A CENTRAL POSITION PROJECTION FORMED ON THE BOTTOM THEREOF, AN INSULATING BASE, AN APERTURE DISPOSED IN SAID BASE FOR RECEIVING THE PROJECTION, BEARING SURFACE MEANS FORMED INTEGRALLY INTO SAID BASE, AND A ONE-PIECE, GENERALLY PLANAR AND C-SHAPED MEMBER HAVING AN EDGE OF ONE END PIVOTALLY SUPPORTED UPON SAID SURFACE MEANS, THE OTHER END OF SAID MEMBER BEING ENGAGEABLE WITH THE PROJECTION OF THE LAMP WHEN THE LAMP IS SEATED IN SAID LAMPHOLDER THEREBY TO PROPEL THE LAMP FROM SAID LAMPHOLDER. 